Many public safety departments now use mobile data networks to provide computer automated dispatch (CAD) services, autonomous vehicle location (AVL) systems, database queries, and photo ID information. The use of such services not only ensures the accurate and reliable exchange of information, but has significantly reduced or eliminated the amount of voice chatter in public safety voice channels and improved access of such voice channels during emergency situations.
However, conventional mobile data services are generally provided by private low speed networks operating in the public safety bands at data rates between 9.2 and 64 kb/s for CAD and AVL systems. Although these systems generally work well for law enforcement, first responder, and other public safety operations, the limited bandwidth of such systems generally cannot support advanced applications such as video streaming and the rapid transmission of large data files. As a result, some advanced applications such as electronic warrants, biometric information, hot list updates, and video communications are generally unavailable or cannot be used in real-time.
In some cases, public safety departments have obtained larger bandwidth data channels by the use unlicensed bands or public cellular networks. However, since these networks provide data services in cells with ranges from a few hundred feet to several miles, and are designed to support consumer grade services to a very large number of customers, these unlicensed and public networks generally do not provide the reliability and isolation from overload that are required to enable the fully integrated use of CAD, AVL, and other advanced public safety applications. Additionally, public cellular networks operating on such standards as for example, CDMA-1X, UMTS/HSDPA, GSM/GPRS, TDMA/EDGE, EV/DO, are generally deployed to maximize capacity, at the expense of reach and reliability. Furthermore, use of such unlicensed and public networks by different departments generally limits the amount of interoperability.